Applicant hereby incorporates by reference Japanese Application No. 2001-146393 (P), filed May 16, 2001, in its entirety.
The present invention relates to etching methods, apparatus and methods for fabricating a semiconductor device. More particularly, the present invention includes certain embodiments relating to etching methods, apparatus and methods for fabricating a semiconductor device, which improve an etching selection ratio of a film to be etched against metal silicide, Si, and photoresist.
In conventional dry-etching methods, a plasma of halogen gas is generated in a processing chamber, and the action of ions, radicals and electrons in the plasma are used to conduct an etching. These methods are known as plasma etching methods.
Many proposals have been made to increase the etching speed while improving the etching selectivity in such etching methods. For example, as one of the etching methods to increase the etching speed at the time of etching silicon and silicon oxide while decreasing the etching speed for photoresist, a method has been proposed in which fluorocarbon etching gas such as CHF3 and the like is used, and the substrate temperature is controlled to be below zero degrees Centigrade when the etching is conducted. This method is advantageous when etching of a Si film or a Si substrate and etching of a SiO2 film are to be conducted at the same time.
Also, in another proposed method to increase the etching speed for Si and to slow down the etching speed for SiO2 and photoresist, SF6 is used as etching gas, and the substrate temperature is controlled to be xe2x88x92100 to 130xc2x0 C. when the etching is conducted (see Monthly Semiconductor World 1998, 1, p58). This method is advantageous when a SiO2 film is not etched, but only a Si film or a Si substrate is to be etched.
Certain embodiments relate to an etching method including supplying etching gas onto a member to be processed, and forming a plasma in at least part of the etching gas for etching the member to be processed by the plasma. The etching method includes maintaining the member to be processed at temperatures of 30xc2x0 C. or lower when etching is conducted, and using gas including a fluorocarbon gas and at least one of O2 gas and O3 gas as the etching gas.
Embodiments also relate to an etching apparatus for etching a member to be processed by plasma, including a maintaining system that cools and maintains the member to be processed at temperatures of 30xc2x0 C. or lower when etching is conducted, a supply system that supplies etching gas onto the member to be processed, and a plasma system that forms a plasma in at least part of the etching gas supplied by the supply system. A gas including a fluorocarbon gas and at least one of O2 gas and O3 gas is used as the etching gas.
Embodiments also relate to a method for fabricating a semiconductor device, the method including forming a dielectric film on a base comprising at least one material selected from the group of a metal silicide and Si. The method also includes dry-etching the dielectric film to form in the dielectric film first and second contact holes that expose surfaces of the base. The amount of etching in forming the first contact hole is less than the amount of etching in forming the second contact hole. The etching gas used for the dry-etching is gas includes a fluorocarbon gas and at least one of O2 gas and O3 gas. The temperature of the base is 30xc2x0 C. or lower when the dry-etching is conducted.
Embodiments also relate to a method for fabricating a semiconductor device, the method including forming a gate electrode on a semiconductor substrate, forming diffusion layers in source/drain regions of the semiconductor substrate, and forming a metal silicide film on the gate electrode and the diffusion layers of source/drain regions. The method also includes forming a silicon oxide film on the metal silicide film. The method also includes dry-etching the silicon oxide film to form in the silicon oxide film a first contact hole located over the gate electrode, and second contact holes located over the diffusing layers in the source/drain regions. The etching gas used for the dry-etching is gas including a fluorocarbon gas and at least one of O2 gas and O3 gas, and the temperature of the semiconductor substrate is 30xc2x0 C. or lower when the dry-etching is conducted.